1. Field of the Invention
The present invention relates to a method of communication suitable for use in, for example, a base station and a terminal apparatus in a radio telephone system, and a base station and a terminal apparatus to which the method of communication is applied.
2. Description of the Related Art
In a mobile communication such as a radio telephone system or the like, multiple access is provided in which a plurality of base stations are provided at a predetermined interval to form a service area and each of the base stations is connected to a plurality of mobile stations (terminal apparatus). In this case, a predetermined transmission band is allocated in advance to each base station; a plurality of transmission channels are set in the transmission band; in the case of a request for communication or the like from each terminal apparatus, any of the transmission channels is allocated to the terminal apparatus; and the terminal apparatus side initiates communication by way of the base station using the allocated transmission channel.
For example, such systems of communication wherein the transmission channels are set include a frequency division multiple access (FDMA), a time division multiple access (TDMA), a code division multiple access (CDMA) and so on.
Referring to each method, the communication system of FDMA system is one in which a plurality of transmission channels are provided by dividing the transmission band prepared by a unit of frequency. The communication system of TDMA system is one in which a transmission channel is divided by a predetermined time unit to form a plurality of time slots within a single transmission channel, each of the time slots being allocated to the terminal equipments to be linked. Therefore, it is possible to link the plurality of terminal equipment using the single transmission channel. The communication system of CDMA system is one in which a specified code is allocated to each of the terminal equipments and a carrier having the same frequency is subjected to spectrum spread modulation by the code for transmitting it to the base station. The receiving side achieves synchronization with each code to identify a signal from a desired terminal apparatus.
In a radio telephone system, even if any of the above systems is employed and a transmission channel is set in accordance therewith, a transmission capacity of data which can be transmitted on one transmission channel is previously determined and hence the transmission capacity cannot be changed depending upon the kind of transmission data. In a general radio telephone system, the transmission capacity of one transmission channel is set so as to be a capacity which allows transmission of audio data for speech.
Recently, while attempts to transmit various data other than audio data by using a radio terminal such as a portable telephone or the like has been made, such a limitation that data of only a predetermined transmission capacity can be transmitted on one transmission channel brings the disadvantage that it takes considerable time to transmit data of a large capacity. In order to solve this problem, it may be sufficient to set a large transmission capacity as the transmission capacity of data which can be transmitted on one channel. However, as the transmission capacity of one channel is increased, a frequency band width of one transmission channel and so on must be set wide to that extent, which consequently reduces the number of transmission channels set in a transmission band allocated to one base station. Moreover, if data of a comparatively small capacity such as audio data is transmitted, the data amount to be transmitted on each of the transmission channels becomes smaller as compared with the transmission capacity of the transmission channel, which disadvantageously causes an ineffective use of the transmission band.
In view of such aspects, it is an object of the present invention to correctly carry out a radio communication such as a radio telephone system or the like even if a transmission capacity is changed.
According to a first aspect of the present invention, a communication resource allocation method in which a second apparatus allocates a communication resource based on a request from a first apparatus includes an allocation request step for transmitting an allocation request signal by the first apparatus to the second apparatus, and a resource allocation step for detecting, by the second apparatus, the allocation request signal to allocate a communication resource. The communication resource allocation is carried out by using a resource of a predetermined amount as a unit.
According to a second aspect of the present invention, a communication resource allocation method in which a second apparatus allocates a communication resource based on a request from a first apparatus includes an allocation request step for transmitting an allocation request signal by the first apparatus to the second apparatus, an acceptance step for detecting the allocation request signal by the second apparatus to transmit a related information to the first apparatus therefrom, a confirmation step for receiving the related information by the second apparatus to transmit an acknowledge signal therefrom for confirmation, and an information transmission step for, after confirmation step, carrying out a communication by the first and second apparatus based on a communication resource allocation made by employing a resource of a predetermined amount included in the related information as a unit.
According to a third aspect of the present invention, a base station for allocating a communication resource based on a request from a terminal includes a reception unit for receiving an allocation request signal from the terminal, a control unit for grasping a condition of a communication resource and for carrying out a communication resource allocation at a unit of a resource of a predetermined amount in response to the allocation request signal, and a transmission unit for transmitting a result of the communication resource allocation by the control unit.
According to a fourth aspect of the present invention, a terminal apparatus includes a control unit for generating an allocation request signal, a transmission unit for transmitting the allocation request signal generated by the control unit, and a reception unit for receiving a result of a communication resource allocation carried out by a base station. The control unit controls communication based on the received result of the communication resource allocation and the communication resource allocation is carried out by using a resource of a predetermined amount as a unit.